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36 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/malloc.h>
47 hash_mflags(int flags)
50 return ((flags & HASH_NOWAIT) ? M_NOWAIT : M_WAITOK);
54 * General routine to allocate a hash table with control of memory flags.
57 hashinit_flags(int elements, struct malloc_type *type, u_long *hashmask,
61 LIST_HEAD(generic, generic) *hashtbl;
63 KASSERT(elements > 0, ("%s: bad elements", __func__));
64 /* Exactly one of HASH_WAITOK and HASH_NOWAIT must be set. */
65 KASSERT((flags & HASH_WAITOK) ^ (flags & HASH_NOWAIT),
66 ("Bad flags (0x%x) passed to hashinit_flags", flags));
68 for (hashsize = 1; hashsize <= elements; hashsize <<= 1)
72 hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type,
74 if (hashtbl != NULL) {
75 for (i = 0; i < hashsize; i++)
76 LIST_INIT(&hashtbl[i]);
77 *hashmask = hashsize - 1;
83 * Allocate and initialize a hash table with default flag: may sleep.
86 hashinit(int elements, struct malloc_type *type, u_long *hashmask)
89 return (hashinit_flags(elements, type, hashmask, HASH_WAITOK));
93 hashdestroy(void *vhashtbl, struct malloc_type *type, u_long hashmask)
95 LIST_HEAD(generic, generic) *hashtbl, *hp;
98 for (hp = hashtbl; hp <= &hashtbl[hashmask]; hp++)
99 KASSERT(LIST_EMPTY(hp), ("%s: hashtbl %p not empty "
100 "(malloc type %s)", __func__, hashtbl, type->ks_shortdesc));
104 static const int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531,
105 2039, 2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143,
106 6653, 7159, 7673, 8191, 12281, 16381, 24571, 32749 };
107 #define NPRIMES nitems(primes)
110 * General routine to allocate a prime number sized hash table with control of
114 phashinit_flags(int elements, struct malloc_type *type, u_long *nentries, int flags)
117 LIST_HEAD(generic, generic) *hashtbl;
119 KASSERT(elements > 0, ("%s: bad elements", __func__));
120 /* Exactly one of HASH_WAITOK and HASH_NOWAIT must be set. */
121 KASSERT((flags & HASH_WAITOK) ^ (flags & HASH_NOWAIT),
122 ("Bad flags (0x%x) passed to phashinit_flags", flags));
124 for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
128 hashsize = primes[i];
130 hashsize = primes[i - 1];
132 hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type,
137 for (i = 0; i < hashsize; i++)
138 LIST_INIT(&hashtbl[i]);
139 *nentries = hashsize;
144 * Allocate and initialize a prime number sized hash table with default flag:
148 phashinit(int elements, struct malloc_type *type, u_long *nentries)
151 return (phashinit_flags(elements, type, nentries, HASH_WAITOK));